Packet-based communication systems allow the user of a device, such as a personal computer, to communicate using computer network such as the Internet. Packet-based communication systems can offer voice over internet protocol (“VoIP”) communication, video calling, instant messaging, voicemail and file transfer. These systems are beneficial to the user as they are often of significantly lower cost than fixed line or mobile networks. This may particularly be the case for long-distance communication. To make use of such systems, the user must install and execute client software on their device. The client software provides the communication connections as well as other functions such as registration and authentication.
A feature of packet-based communication systems is that the client software can maintain a history of the communication events that are occurring between users. This enables a record of conversations and events to be maintained, which is useful for enabling users to resume conversations or refer back to previous events. The history of communication events comprises the text of instant message chats or SMS messages, records of the time and duration of voice or video calls or voicemails, and file transfers sent between users. As the number of communication events instigated or received by the client software increases, a continuous record of events is created. The history is viewable by the user as a long formatted text document in a form similar to a document such as a webpage, in which the user is able to freely scroll the document and select arbitrary amounts of text and other content.
However, the amount of data accumulated in the history of communication events performed over the communication system can be very considerable. The history can easily reach tens of thousands of messages, resulting in documents that are hundreds of pages long. Handling documents of this length (which contain complex formatting) is very difficult, due to the requirements placed on the consumption of system resources. In addition, the navigation of documents of such length is difficult and cumbersome for the user.